Muscle Car Suspension Basics - Turning The Corner

If You Want To Maximize Handling, You Have To Understand The Basics Of Suspension Design And Spend Money Where It Counts Most

DSE's innovative Swivel-Link rear control arm features an outer section that swivels around the inner shaft. Consequently, side-to-side rearend binding is dramatically reduced. The compliance built into the control arms allows the use of softer bushings for reduced road noise.

"Leaf springs will always be around in some form or another because they're simple and inexpensive. If you can get the ride height and spring rate you need out of them, then they'll work just fine in most street cars as long as you're not making a ton of power," explains Tom Brown of Heidt's. "However, the only way to adjust the ride height and roll center with leaf springs is by using spacer blocks. Upgrading to an aftermarket four-link system allows changing the suspension geometry and ride height by adjusting the length of control arms and coilovers. Unlike a drag-oriented four-link, street four-links are designed to allow the rearend to roll and articulate, which gives you excellent forward bite and handling. They're the best of both worlds, and usually lighter than a leaf spring system as well."

Control ArmsDue to the impressive appearance of tubular front control arms, you might assume that their chief benefit over a stock unit is strength. However, as Kyle Tucker points out, that isn't necessarily the case. "It's true that the suspension endures incredible loads, but deflection with stock control arms isn't really an issue in most situations, and most people wouldn't be able to feel it anyways," he explains. "The truth of the matter is that it's much easier to manufacture a control arm out of tubular steel than it is to invest in the equipment necessary to make stamped control arms. While the increased strength of aftermarket control arms may be necessary when matched with sticky tires, their main benefits are improvements in suspension geometry."

Typically, the mounting points of the control arms and ball joints must be moved to achieve any appreciable camber gain. For the most part, these anchoring points can not be changed without seriously hacking up the frame or compromising other aspects of suspension geometry, such as the Ackerman and tie-rod angles.

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Although often overlooked, jounce bumpers are cheap insurance. They prevent the lower control arms from hitting the frame when subjected to severe bumps and act as a progressive-rate spring when compressed.

"Front suspension design is the most sophisticated system on the entire car. Everything is interrelated, and you can't change one thing without affecting something else," Chris Alston explains. "Properly designed control arms can slightly improve the camber curve and move the caster angle, but to really make a difference you have to move the pickup points." Furthermore, the built-in shock mounts offered in most aftermarket control arms eliminate the need to modify a stock arm when converting to coilovers.

Front ClipsFor those with well-endowed bank accounts, a new front subframe assembly is the pinnacle of suspension upgrades. Although quality aftermarket components bolted to a stock subframe will get you 90 percent of the way there, an aftermarket clip offers just a wee bit more performance-and looks trick to boot. The limitations of how much factory suspension geometry can be tweaked are no longer relevant with an aftermarket clip, as the mounting points of the control arms, tie rods, spindles, and coilovers can be positioned wherever a suspension designer chooses. "By starting with a clean sheet that doesn't force us to work within the constraints of the factory design, we can move all the suspension mounting points to improve the camber gain and caster while eliminating bump steer," Tom Brown explains. "Additionally, aftermarket clips provide more room for bigger tires, and can be setup with a variety of motor mounts to simplify engine swaps."

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Muscle Car Suspension Basics - Turning The Corner

You always want to fine tune with the sway bars and shocks. Also, as soon as you put more load into a car with stiffer springs and sway bars, you need to strengthen the chassis with subframe connectors.-Kyle Tucker

As a result of a larger diameter and a shorter swing arm length, the bottom sway bar is substantially stiffer than the unit on top. In practice, this is because the front sway bar (bottom) must endure greater cornering loads than the rear bar (top). However, differences in sway bar design between a matched set of front and rear sway bars clearly illustrates the effects of diameter and swing arm length on overall stiffness.

The splined ends on this Chassisworks rear sway bar allows dialing in preload. This eliminates slop between the bar and the endlinks for improved responsiveness.

The spring rate of a coil spring is determined by the wire thickness of the coils, the number of coils, and how tightly the coils are wrapped in a circle (diameter). Linear-rate springs, shown here, have equally spaced coils. On progressive-rate springs, the top coils are closer together than the bottom ones.

As long as your car isn't a fire-breathing 500hp beast that will see lap after lap on a road course, an aftermarket leaf spring suspension system will suffice. This first-gen Camaro DSE kit feature 175-lb/in tapered springs with an antifriction pad wedged between the leaves, which reduces friction and improves ride quality. A matching set of shocks and heavy-duty shackles are also included.

Although air suspension systems trace their roots back to show cars, Air Ride Technologies has proven that air suspensions can more than hold their own on a road course. Air is an excellent springing medium; it gets stiffer the more that it's compressed. Likewise, it can also be set up to behave in a very linear fashion. Unlike traditional coilovers, an air suspension can be adjusted at the touch of a button. These trick Shockwave units feature integrated double-adjustable shocks.

Shocks damp spring motion by converting kinetic energy into thermal energy. Under rigorous use, a shock will begin to fade and lose its damping ability if it can't dissipate heat quickly enough. To combat this effect, DSE has designed an optional remote-mount reservoir canisters that reduce shock fade by increasing fluid capacity.

One of the wildcards when installing a front coilover conversion is the difficulty of mounting them. This Chassisworks setup for fourth-gen F-bodies bolts directly to the stock control arms on the bottom and the factory shock mounts on top by using a supplied adapter. Other vehicles may require bolting or welding new brackets onto the body or frame. Some coilovers can be mounted upside-down, which reduces unsprung weight.

As with the front suspension, rear coilover conversions can sometimes mount to the stock shock mounts, but certain cars require installing new brackets to the rearend housing or frame. This Chassisworks universal coilover kit includes a crossmember for the upper coilover mounts and ears for the rearend housing, and both must be welded in place. The adjustable lower shock mounts allow tweaking ride height without affecting suspension travel or spring rate.

Unlike a suspension optimized for a road course or the street, an autocross setup can take the stiff-spring-and-small-bars approach to achieve proper roll stiffness since it operates on a smooth surface. This arrangement would not respond well to elevation changes on a road course and would ride terribly on the street.

In cars originally equipped with leaf springs, like first- and second-gen Camaros, upgrading to a four-link may or may not be a bolt-in affair. The lower links attach to where the leaf springs used to reside, but the upper links require installing new brackets to the frame. Heidt's four-link kit for first-gen Camaros features a bolt-in upper control arm mount, which is also the rear cradle to which the coilovers attach. While not quite as adjustable as a dedicated drag four-link, the Heidt's design includes a Panhard bar to locate the rearend and offers far more flexibility when subjected to lateral loads to help prevent binding.

Deflection in the bushings can harm suspension geometry and limit the rear suspension's ability to put the power down. Although they transmit the most noise and require regular lubrication, Heim joints virtually eliminate deflection, and they also enable the rearend to articulate from side to side to reduce binding.

Improved strength is just one of the many benefits of an aftermarket control arm. This piece from DSE features an adjustable cross-shaft, which allow the caster angle to be changed by sliding the entire control arm forward or backward. Adjusting caster angle enables fine-tuning the steering feel and straight-line stability.

Many aftermarket front control arms, such as these from Air Ride, position the shock mount lower than stock. That opens up room for a taller shock, which results in greater suspension travel and an improved ride.

Alternatives to deflection-prone rubber bushings and noise-prone Heim joints are urethane and Delrin. While urethane bushings are stiffer than rubber, many experts suggest avoiding them because urethane squeaks, requires regular splashes of grease, and still deflects more than many suspension tuners would like. Delrin, a thermoplastic manufactured by DuPont, is becoming more popular due to its strength and low friction.

DSE's innovative Swivel-Link rear control arm features an outer section that swivels around the inner shaft. Consequently, side-to-side rearend binding is dramatically reduced. The compliance built into the control arms allows the use of softer bushings for reduced road noise.

Although often overlooked, jounce bumpers are cheap insurance. They prevent the lower control arms from hitting the frame when subjected to severe bumps and act as a progressive-rate spring when compressed.

For maximum effectiveness, springs and shocks should be mounted as close to the ball joints as possible, and as close to vertical as packaging constraints allow. Failure to do so yields a large linkage ratio, which reduces the effectiveness of the springs and requires a stiffer rate to compensate. One of the few methods of dialing in more camber gain into the front suspension is with a taller spindle, which raises the location of the upper ball joint.

Tremendous gains in handling are possible with aftermarket control arms, coilovers, and sway bars. Aftermarket front clips go one step further with revised linkage pickup points for optimized suspension geometry. Although Heidt's street rod front clips are based on Mustang II hardware, its new muscle car subframe assemblies are a clean-sheet design. They're available for first- and second-gen Camaros and '68-72 Novas.

It's impossible to know what you suspension's telling you if it's communicating through a sloppy stock steering box. This unit from DSE, which is a direct replacement for the common GM 800 box used from 1964 to 1992, dramatically improves steering feel due to a reduction in internal friction. Furthermore, it is six pounds lighter than stock and features a 12.7:1 steering ratio.

There is an abundance of parts for the poplular Camaro, which includes control arms, and we have set a list of companies that offer what you're looking for in terms of performance, style, and budget. Camaro Performers Magazine » Read More

In this tech article CORVETTE FEVER takes a look at Speeddirect's Shark Bite control arms and coilovers for C2 and C3 Corvettes, and install a set on a 1967 Chevrolet Corvette - Corvette Fever Magazine » Read More